270 Mr. C. F. M. Swynnerton on the 



apparently exaggerated conspicuousness or elaboration of 

 ornament. 



To sum up : — 



Distinctiveness and conspicuousness will, in the main, 

 though by no means exclusively, have been selected in 

 relation to the need for recognition, (1) by friends, (2) by 

 enemies ; and both these factors will very commonly have 

 contributed to the production o£ the distinctive charac- 

 teristics of even a single species. I refer not only to 

 distinctiveness of appearance, but to any characteristics — 

 call-notes, smells, displays, &c. — that may be useful for 

 differentiation by either friends or enemies. 



" Mimicry^' : special protective resemblance. — Special re- 

 semblances, both to other animals and to particular inanimate 

 objects, were much noticed and written of at a quite early 

 date, the first recorded case being Aristotle^s of the resem- 

 blance of a cuckoo to a hawk.. But the first author who 

 definitely applied to them a selectionist interpretation, only 

 four years after Darwin and Wallace's famous joint essay, 

 was H, W. Bates, of Amazons fame. In his classical paper, 

 " Contributions to an Insect Fauna of the Amazons Valley ^' 

 (Trans. Linn. Soc. xxiii. pt. iii. 1862, p. 495), he enumerates 

 cases of resemblance both to inanimate objects and to 

 unrelated animals, links them by means of a longicorn group, 

 some of the members of which resemble the former, some the 

 latter, and claims the same principle for both. Moreover he 

 maintains that in a day-flying moth resembling a wasp, the 

 resemblance is " to protect the otherwise defenceless insect 

 by deceiving insectivorous birds," and suggests that, in 

 butterflies, the " mimicry " of the Heliconidse by Leptalis 

 is analogous to this, only that where the wasp is avoided for 

 its sting, the Heliconidse, with a peculiar smell, abundant, 

 and never seen to be attacked, " are unpalatable to insect 

 enemies." He mentions " two instances of mimicry in 

 birds .... communicated to me by my old travelling- 

 companion, Mr. A. R. Wallace" (the now classical case 

 of Philemon and Mhneta) ; and he suggests natural selection 



